"In the case of the US Military, they have a unique problem where they are one of the biggest and wealthiest buyers of really old parts. Military designs have shelf lives of decades, but parts have production cycles of only years."

A solution:

"A final option could be to establish a strategic reserve of parts. A production run of military planes is limited to perhaps hundreds of units, and so I imagine the lifetime demand of a part including replacements is limited to tens of thousands of units. I can fit ten thousand chips in the volume of a large shoebox"